Over the years she has argued her case tirelessly, and has gained some allies. Volcanism has acquired new scrutiny as a possible cause of mass extinctions. The worst mass extinction in the fossil record, at the end of the Permian — the last period of the Paleozoic Era — seems to have coincided with massive volcanic eruptions.
“Her opponents have failed to adequately address the issues she has raised, and often choose to ignore her work because — to paraphrase a phrase from elsewhere — what she has discovered are inconvenient truths that cast severe doubt on a model that they have been peddling,” says Andrew Kerr, a petrologist at Cardiff University in Wales who supports Keller.
Ted Nield, editor of the journal Geoscientist and author of the book Incoming!, which features a chapter on Keller, says, “Gerta is the sort of person for whom universities were created — and for whom the protection of tenure is so vital. She has had the guts and determination to stand out against an unstoppable bandwagon that itself started off as heresy but which has quickly become a rather oppressive orthodoxy.”
Is she right? Nield says he can’t say. But he finds Keller to be a compelling figure — and has written about her despite criticism that she doesn’t deserve the attention.
The impact theory for the K/T mass extinction isn’t universally acepted, but any rival hypothesis carries the heavier burden of proof at this point. The impact theory is based on multiple lines of evidence at both the macroscopic and microscopic level. It also has the lovely feature of parsimony. It’s not very complicated. In science, simpler is usually better. And if a giant rock hit the Earth very close to the time that all the dinosaurs disappeared, it’s hard to think of that as a mere coincidence and not a matter of causality.
But you can say the same thing about the Deccan Traps.
The K/T event, says Paul Wignall of the University of Leeds, “qualifies as the biggest coincidence in world history — peak volcanism coincided with the impact of the largest meteorite to hit in the past billion years.”
The K/T extinction controversy shows no sign of abating more than 30 years after the Alvarez paper was published. In a 2010 review of the issue in Science, German geophysicist Peter Schulte and 40 co-authors declared flatly that the Chicxulub impact alone triggered the mass extinction. The scientists said multiple lines of evidence, including the pattern in which material had been ejected from the crater, place the impact at the K/T boundary. Deccan volcanism, they wrote, would have resulted in “only moderate climate change” during the last 400,000 years of the Cretaceous.
That article stirred the pot again, and a number of scientists published letters to Science objecting to the case-closed conclusion of Schulte and his co-authors, and arguing for multiple causes of the extinction. Keller also weighed in, reiterating her argument, in a letter, that Chicxulub predates the K/T boundary and that Deccan volcanism could have had as dire an effect on global climate as the impact event.
Keller says of her critics, “The reason they cannot accept it is because it would mean they would have to admit that their theory was wrong.” Few people, she says, could admit that for 20 years, “they’ve been preaching up the wrong tree.”
She adds, “That’s probably a wrong way of saying it.”
“Barking,” I suggest. Barking up the wrong tree.
She laughs, and says, “I once said, ‘You can kill this bird with two stones.’”
Keller is now 67, a successful renegade. She’s been married for three and a half decades to the New York University mathematician Andrew Majda. In her third-floor office in Guyot Hall, ornamental plants — jade, euphorbias, bougainvillea, Christmas cactus — bask in the sunlight streaming through tall windows. She has antique filing cabinets and chairs, rescued from one of the department’s overhauls some years back. Her shelves are filled with books and manila folders, hardly a square inch unoccupied.
“It’s a crazy life, but it’s the best I could do,” she says.
She chose her passion well: “If you like to sit on a beach and watch the sundown, if you like to travel and experience different culture, then you should become a geologist, because you can always dream up a project involving rocks anywhere in the world, and somebody’s going to pay you for that.”
It’s easy to forget, as we discuss the events that ended the Cretaceous period, that we’re speaking of disasters, of global catastrophes. It was so long ago. It doesn’t feel, to me, completely real. I asked her if it could happen again — meaning another volcanic eruption on the scale of the Deccan Traps.
“It will happen again. Of course,” she says. “There’s nothing we can do. These eruptions are absolutely unbelievably giant. What would we do? We’re causing extinctions even without those eruptions. We’re right in the middle of one.”
There’s a subtle, slightly political element to Keller’s thesis: Her view of volcanic activity causing extinctions more gradually has an echo in the current concerns about climate change. She says of the impact scenario — the Hammer of God bringing instant catastrophe — “It’s a very sexy, beautiful theory. It appeals to everyone’s imagination. It’s simple. It absolves you from having done anything that might have caused a mass extinction.”
She draws another lesson from the forams:
“If we take the analog to these critters we are studying in the ocean, the more specialized we get, the less we are going to survive. We are specialized. Rats and cockroaches are not specialized at all. They’ve been the same for the last 250 million years. They’re going to survive. But I have my doubtswe will.”
“It’s a comforting thought, isn’t it?” she says sarcastically.
We have lunch at Frist, and she ruminates on her status as a heretic (she can’t be described as an apostate because she never believed in the orthodoxy).
“I would prefer everyone to love me instead of hate me. But that’s not going to happen,” she says.
Hate, really? How do they manifest that, I ask.
“Stare. Some of them shout. ‘You’re wrong. You don’t know what you’re doing.’”
We then visit her lab in Guyot. I look through a microscope at some of her forams. She shows me some big ones, the diverse ones from before the K/T extinction.
“They expend a lot of energy being pretty and big,” she says.
Magnified 120 times, they look to me like little white blobs.
Through another microscope I examine the post-extinction forams. Smaller, yes. But still blobby.
“The difference is enormous, as you can see,” she says, though I find it challenging to make head or tail of these little things.
This kind of work takes a trained eye. Patience. Doggedness. These are not charismatic megafauna — they’re the size of grains of salt, or smaller. And Keller has lots of them. She has a tremendous archive of foraminifera, packaged and labeled in drawers in a room adjacent to the lab.
Whoever wins the K/T debate will not win because of a vote. Science isn’t a democracy. Yes, Keller still is regarded as a contrarian, but that may not be a permanent status. When I email my freshman-year geology professor, Ken Deffeyes *59, and ask him about Keller’s contrarianism, he writes back:
“The winner of a war gets to write the history. Gerta is a contrarian only if she loses.”
Joel Achenbach ’82 is a writer at The Washington Post.